Compatibility:MERV-13 Air Filter for Purecare 780S Air Filtration System. Filtration grade:High efficiency MERV-13 filter captures 90% of 3-10um particles. Quickly and safely filters airborne particles to protect internal components from clogging while improving your work environment. Filter dimensions:4 Pack Filters for AlorAir air filtration system 13.11 inch X10.35 inch X0.71 inch Easy to install:Simply follow the arrow signs to determine the correct airflow direction and place the new filter to complete the entire replacement process. Long filter life:Recommended to replace the filter every 6 months to keep your MERV-13 filter running at peak performance. Warm Tips: In order to obtain the best results, please replace the filter every 120 to 180 days. (In case of frequent use in the workshop, replace the filter according to the use). If you have any questions, you can call us directly, ready to assist you. IMPORTANT: Does not meet California air cleaner regulation requirements; cannot be shipped to California.